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A loop device is a pseudo-device which doesn’t correspond to a real, physical block device, but can be used to make a file appear and be treated like one. To manage loop devices on Linux, we can use the losetup command: the utility let us create new loop devices, detach them and retrieve information about existing ones.

Qcow2 is the default virtual disk storage format used by Qemu (qcow stands for qemu copy-on-write). This image format makes use of thin provisioning, so, after we initially set the maximum virtual size of a disk, space is actually allocated only when used, but not made available back to the host when freed.In this article we see how to “sparsify” a qcow2 disk image to reclaim available space, how to expand it or shrink it, and how to manage the partitions layout on it from the host system, connecting it by using the NBD protocol.

In a previous article, we saw how to create kvm virtual machines from the command line; in this tutorial, instead, we learn how to access and modify virtual machines disk images, using some utilities which are part of the libguestfs package on the most commonly used Linux distributions. Those tools let us perform a variety of tasks.

When using Linux on mobile devices such as Laptops, it is very important to tune the right kernel parameters in order to optimize battery life. Tlp is a highly customizable, free and open source command line utility released under the GPLv2 license (the source code is hosted on github) created with this exact goal. In this tutorial we see how to install Tlp on some of the most used Linux distributions, and how to configure it.

Vim is one of most used and famous text editors on Linux and other Unix-based operating systems. It is free and open source software, based on the original Vi editor (Vim stands for Vi IMproved) and mainly developed by Bram Moolenaar. The editor can be setup by editing the ~/.vimrc configuration file, and by using a vast range of plugins. In this article we see how to improve and customize the Vim status bar by installing Powerline, a nice plugin written in Python which can be also used to customize the Bash and Zsh shell prompts.

If you already have some experience as a Linux system administrator, chances are you know what cron is and what it does. If you’re just starting working with Linux, it’s essential knowledge that will certainly serve you later. Either way, if you already have the knowledge, this article will refresh it. If not, you will get a guide to start you up. So you’re only expected to have some basic knowledge of Linux systems and, as usual, a desire to learn.

When performing digital reconnaissance or penetrating testing, it’s important to fingerprint a network by understanding what operating system is used on a remote a host. Nmap is a great tool for this job. Although normally associated with the cybersecurity field and penetration testing, Nmap can also be used for benevolent purposes, such as a system administrator taking an inventory of what operating systems all the systems on his network are running.

In a previous tutorial we saw the basic concepts behind the usage of Tkinter, a library used to create graphical user interfaces with Python. In this article we see how to create a complete although simple application. In the process, we learn how to use threads to handle long running tasks without blocking the interface, how to organize a Tkinter application using an object oriented approach, and how to use Tkinter protocols.

Tkinter stands for “Tk interface”: the package with the same name on many Linux distributions provides the Python bindings for the Tcl/Tk GUI toolkit. Although other graphical toolkit can be used from Python, like Qt or GTK, Tkinter is the standard (the Python IDLE editor and development environment is written using this toolkit, for example) and probably the easiest to work with. In this tutorial we see the basic concepts behind the usage of Tkinter and how to create and interact with some of the most used widgets.

The Z-shell (zsh) is a modern and very powerful shell: it incorporates and extends many feature of other shells, like Bash. Although it can be used as a powerful scripting language, it is mainly aimed at interactive use, since one of its more prominent feature is the advanced tab completion system. In this tutorial we see how to install zsh in the most commonly used Linux distributions, see what are its startup and shutdown files and how to perform the basic configurations.

Linux Unified Key Setup (LUKS) is the de-facto standard block device encryption format used on Linux-based systems. We already discussed some of the features provided by it in a previous tutorial about using a file as a LUKS device key. When using LUKS, encryption metadata is stored on the header which is created at the beginning of the encrypted device (a copy of the header is created at end of the device for redundancy, when using LUKS2).If desired, it is possible to specify that the header should be detached from the device: in this tutorial we see how.

Web scraping is the process of analyzing the structure of HTML pages, and programmatically extract data from them. In the past we saw how to scrape the web using the Python programming language and the “Beautilful Soup” library; in this tutorial, instead, we see how to perform the same operation using a command line tool written in Rust: htmlq.

Fonts are a really important part of the user experience. On the most commonly used Linux-based distributions, there are many packaged fonts which can be installed using the native package manager. Sometimes, however, we may want to install some fonts manually. In this tutorial we see how to perform such operation, and, more generally, how fonts are managed on Linux.

It’s well known that videos are not nearly as easy to save from a website as things like images or text. Although web browsers do not feature a default way to save videos directly to our hard drive, open source projects like yt-dlp and youtube-dl fill this gap quite nicely.

BASH (Bourne Again SHell) is the default shell in practically all Linux-based operating systems. All the commands we write in the terminal are interpreted by the shell, and become part of its history. In this tutorial we see where the shell history is saved, and how to manage it using the “history” built-in command and some environment variables.

We already talked about using flatpak packages in a previous tutorial: with this technology we universally distribute applications, which are packaged together with their dependencies and run inside a sandbox, isolated from the rest of the system. In this tutorial we see how to build and distribute an application inside a flatpak.

Tagging music files is a way of keeping a music library well organized and let us search for songs on the base of Artists, albums, genre and other parameters. Many graphical and command line applications exist on Linux to manage tags for audio files, like Picard or Quodlibet. Most of those applications are written in Python and use the “mutagen” module at their core. In this tutorial we learn how to use it directly.

MySQL is probably the most famous Relational Database Management System (RDBMS). Developed as a free and open source software, it was originally backed by the MYSQL AB company, but is now owned by Oracle. In MySQL the “storage engine” used for a table determines how data is handled. There are several storage engines available, but the most used are InnoDB and MyISAM. In this article we see what are their distinctive features and the main differences between them.

There are a number of dangerous commands that can be executed to crash a Linux system. You may find a nefarious user executing these commands on a system you manage, or someone may send you a seemingly harmless command, hoping that you will run it and crash your computer.

Dracut is a tool used to build initramfs cpio archives. It originated, and is mainly used on Fedora and the other distributions that are part of the Red Hat family, but can be used also on community distributions like Gentoo, and Archlinux. The application functionalities are organized in modules.